Kerr McCosh Monoblock Problem

[willbewill]

Some more info:

http://www.audiohifi.biz/sound/amplifier/thread156.html

[willbewill]

And even more pics








http://www.audio-kontakt.com/forum/viewtopic.php?p=73184&sid=97405ff35e2394cd95cc2d8ec5312d0a

[autobayer]

I love them - always did since I first saw them.
They have character, you can see that.
Lucky you 
C

[rfgumby]

Oh man, that passive pre I made for Woody was almost perfect!  Way better than those pics of the integrated.

I tried so hard to make sure that stayed as accurate as possible even though it was a complete rebuild to passive.   Wish we still had that one floating around our friends, that had some really nice parts in it.  It also took a lot of fiddling to get the knobs and script to work correctly with the original face plate.  Oh well, I hope somebody is enjoying it.

Neat pics Malcolm, thanks.

[nigel]

Ooh, that's interesting - looks like these specimens have a choke in the power supply, which yours didn't have, Malcolm. Lookng back through the pics, I can see that the mounting holes are there, though. I wonder what happened there - were they removed from yours, or did Kerr McCosh stop fitting them, later in production? 
We got the hum down very low, in the end, so they didn't need a choke for that reason. I suppose it would have lowered the power supply impedance a little, but I'm not convinced that would have made much difference.
Anyway, I still say they sounded better than the Leaks 

[reinderspeter]

My guess would be the choke was put in afterwards, like the blue electrolytic. They both look too new.

[Rogers Wah Wah Rabbits]

well there's not a day goes by that i regret selling that Kerr pre amp and funny enough i was talking to the chap i sold it too just the other week  ( local scottish actor ) and he wants to sell it again  I'm hoping i didn't seem too desperate to buy it back .....anyway meeting him tomorrow so im hoping he'll say yes

[rfgumby]

Oh, cool,   Good luck Paul.   I might even be interested in helping it get back into the hands of a friend here.

[willbewill]

Excellent Paul - all the best with it - give Brian (I have got the right one?) my best

[Wout]

What a fabulous looking preamp. 

[willbewill]

What a fabulous looking preamp. 

A couple more shots of it:

[Rogers Wah Wah Rabbits]

I might even be interested in helping it get back into the hands of a friend here

Scott if i manage to get it back it wont be going anywhere else ever !!!

Malcolm yeah Brian is the chap that bought it ( Andra in Rab C ) and i have told him to name his price no matter how much he wants for it  

[bluemike]

Sweet looking honey

[Chris65]

A couple more shots of it:

Sweet work Scott, we never saw these sides before. How'd ya do the labelling?

[rfgumby]

Sweet work Scott, we never saw these sides before. How'd ya do the labelling?

Those are clear background label maker labels with the line sanded aluminum jack field panel clear coated
with lacquer to lock the labels and keep the aluminum from dulling and oxidizing.   Looking at it now, I should have had a Kerr logo made up for the open area in the middle.

That passive has Cardas wiring, a DACT stereo attenuator, individual TDK attenuators for each channel, Cardas jacks and a top shelf Elma two deck input selector switch.  The channels are separated by the original steel divider between the top and bottom.  So Paul stepped up and paid for top shelf passive parts.  Of course we could have gone with tranny based attenuation but that would have ended up even more costly and fitment in the factory divided chassis became tricky.  

There is a mono switch, but it acts oddly.  It's just a simple summing switch which bridges the hot signals of each channel.  I've used that function before, but Paul had problems with its function.  I know the phases are correct, but there are also phase switches for the channels as well, so you can come up with all sorts of funky arrangements, like guitar pickup phase switching.  Any Guru's out there know why that interaction occurs?  I've never had one fight quite like that before.   Aside from that though, it's a really cool piece.